For centuries, even millenniums, solid wood products have been used to manufacture and construct homes, doors, door jambs, window frames, window jambs, cabinetry, furniture, decks, fences, and the like. The persistence in using solid wood as a fundamental decorative and structural mainstay to create and decorate such products has been primarily based upon a devotion to traditional construction and manufacturing procedures, a relatively low cost for wood, and an abundance of resources.
Within the annals of history, it has only been recently that a need for alternative lumber products has been acknowledged. For example, the last few generations have seen the advent of plywood having multiple layers of thin shaved wood fibers that are pressed into a bi-directional sheeting or sheathing. We have also seen the introduction of pressboard, Timberstrand, and the increasing use of cardboard.
It has only been within the last two decades that the government, industry, and public have been informed of a need to conserve the forests and particularly the rain forests. The reasons given for conserving such forests include protecting the earth's ozone layer, maintaining a genetic pool of plant life that may be important for future medical advances, and protecting endangered species.
Irrespective of the validity or invalidity of the current positions promoted by many naturalists and scientists, it has become clear that indiscriminate removal of trees is a thing of the past.
Industries that rely heavily upon the supply and use of solid wood products are finding that such resources are becoming increasingly scarce and much more costly.
Heretofore, exterior and interior residential doors were typically manufactured from solid wood planks that were milled to form solid wood stiles, rails, and panels. The stiles, rails, and panels were then fitted and secured to each other to form a paneled or flush door.
However, the production of solid and milled wood doors requires the stockpiling and use of a large quantity of very expensive, high-quality wood. With the depletion of the world's old-growth forests, such high-quality wood is becoming prohibitively expensive and difficult to acquire and store. In addition, such doors do not provide an effective insulative barrier.
When manufacturing patio doors, one or more of the milled panels that would otherwise be used in a traditional door are replace with sheets of heavy, thick glass. The use of such glass does not alleviate the practice of using solid wood planking or dimensional lumber to support the glass and form the general framework of the door. It should be remembered, however, that the use or placement of glass within a door significantly decreases the energy efficiency of the door.
Due to the foregoing reasons, economic reality is forcing many companies and whole industries to look for alternative sources of decorative and/or structural materials. For example, several companies are now manufacturing doors and windows that have aluminum and/or vinyl frames and/or skins. The exterior plastic or metal skin on these doors is actually overlaid upon and applied to an interior framework constructed of solid wood stiles and rails. Many of such doors have a hollow interior core and are not very energy efficient.
Another variation of door structure is to encapsulate a thin sheet of batten fiberglass or foam insulating material within the otherwise hollow core. Solid wood stiles and rails are again used about the perimeter or periphery of the door. The fiberglass or foam insulating material is juxtaposed between a thin outer and inner exterior plastic or metal skin.
If the foam is injected into the hollow core, it is highly likely and probable that an air pocket or void will result wherein no foam is located. This is a very common problem with manufacturing such doors.
If a raised panel design is desired, a compression press can be used to indent both the outer skin and the insulating material to form the desired design. Although this manufacturing process produces a door having admirable energy conserving capabilities, the end product typically has a thin, stretched plastic or metal surface that is not aesthetically appealing.
Such laminated, thin skinned doors are significantly different from a traditional stainable wooden door. The perimeter of such doors reveals either sharp plastic edges or folded metal edges. Such composite doors do not have the appearance, sound, or weight that is expected of a high-quality wooden door.
Even though the amount of wood fiber used within such doors may be partially reduced, due to the use of a plastic or metal outer skin and partially injected foam central core, solid wood stiles and rails are still required.
The following disclosures relate to various types of known door structures and/or methods of manufacture thereof: Malarkey (U.S. Pat. No. 2,334,113; issued Nov. 9, 1943); Lincoln, Jr. (U.S. Pat. No. 2,791,809; issued May 14, 1957); Weyant (U.S. Pat. No. 3,286,424; issued Nov. 22, 1966); Charles (U.S. Pat. No. 3,334,464; issued Aug. 8, 1967); McGhee (U.S. Pat. No. 3,345,780; issued Oct. 10, 1967); Bainter et al. (U.S. Pat. No. 3,969,868; issued Jul. 20, 1976); Imperial et al. (U.S. Pat. No. 3,987,588; issued Oct. 26, 1976); Bursk (U.S. Pat. No. 4,034,511; issued Jul. 12, 1977); Weyant (U.S. Pat. No. 4,064,655; issued Dec. 27, 1977); Governale (U.S. Pat. No. 4,114,319; issued Sep. 19, 1978); Day et al. (U.S. Pat. No. 4,147,004; issued Apr. 3, 1979); Seely (U.S. Pat. No. 4,152,876; issued May 8, 1979); Teleskivi (U.S. Pat. No. 4,282,687; issued Aug. 11, 1981); Andresen (U.S. Pat. No. 4,294,055; issued Oct. 13, 1981); Hagemeyer (U.S. Pat. No. 4,630,420; issued Dec. 23, 1986); Tix (U.S. Pat. No. 4,726,148; issued Feb. 23, 1988); Hagemeyer (U.S. Pat. No. 4,876,838; issued Oct. 31, 1989); Green et al. (U.S. Pat. No. 4,888,918; issued Dec. 26, 1989); Strom et al. (U.S. Pat. No. 5,020,292; issued Jun. 4, 1991); and Schield et al. (U.S. Pat. No. 5,022,206; issued Jun. 11, 1991).
The inventor believes that the cited disclosures taken alone or in combination neither anticipate nor render obvious the present invention. These citations do not constitute an admission that such disclosures are relevant or material to the present claims. Rather, the foregoing citations relate only to the general field of the disclosure and are cited as constituting the closest art of which the inventor is aware.